Method of making a ribbon blown glass article

ABSTRACT

A method and apparatus is disclosed to produce a blown glass article on a ribbon machine having a self supporting closed end. Said ribbon formed glass envelope has a cylindrical neck portion terminating at one end in a bulb portion of larger cross sectional dimensions and which includes the self supporting base end. The sides of said glass envelope can be curved or flat and with said self supporting base also being of a curved or planar contour. A novel mold construction permitting said glass envelope to be blown on a ribbon machine comprises a pair of cooperative halves forming the sides of the blown glass envelope in a central cavity in which further includes a separate base part located at the lower end of said cavity to shape the self supporting base, said base part of the mold being provided with reciprocal motion in a vertical direction.

This is a division of application Ser. No. 519,436, filed Aug. 1, 1983.

BACKGROUND OF THE INVENTION

Ribbon blown glass envelopes have been traditionally formed on a ribbonmachine with two-part molds having a partible construction and whichrotate while encircling a hollow molten glass blank. Said conventionalglass molds have been generally provided with a paste coating of thecentral mold cavity along with vent openings to form a steam cushionagainst which the glass envelope is blown while said mold halves arerotating. Although the bulb portion of a glass envelope blown in theconventional manner has included cylindrical as well conical andspherical shapes, all of these shapes terminated at the closed end ofthe bulb portion in a spherical contour preventing the blown articlefrom physically supporting itself. Accordingly, such limitation hasretarded any wider utilization of conventional ribbon blown glassenvelopes in a variety of end product applications including liquidcontainers and even lamp glass envelopes requiring a relatively flatface portion to serve as a lens member in the lamps.

The present invention relates to novel means whereby glass articles ofvarious types are blown on a ribbon machine in a novel mold constructionwhich shapes the closed end of the glass envelope to provide aself-supporting base contour. More particularly, said novel moldconstruction includes three basic parts which cooperate in forming abulb shape terminating in a flattened contour sufficient to permit theglass envelope to be self supporting, that is to stand alone withoutadditional physical support. The basic mold design of the presentinvention includes a pair of cooperative partible halves forming thesides of the blown glass envelope in a central cavity and which furtherincludes a separate base part located at the lower end of said cavity toshape the closed end of said blown glass envelope into the desiredself-supporting contour, said base part of the mold being provided withreciprocal motion in a vertical direction.

Accordingly, an important object of the present invention is to providea ribbon blown glass envelope having assorted shapes for various endproduct application wherein the bulb portion of said envelope terminatesin a self-supporting contour.

Another important object of the present invention is to provide ribbonblown glass envelopes having either curved or planar sides together withan integral self-supporting base contour which can also be planar orcurved in shape.

Still another important object of the present invention is to provide animproved method for manufacture of said novel glass envelope on a ribbonmachine by means of a novel mold design.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a ribbonformed glass envelope having a cylindrical neck portion terminating atone end in a closed bulb portion of larger cross-sectional dimensionsand which includes a self-supporting base contour. In various preferredembodiments, the glass envelope is blown from either molten hard or softglass compositions of a conventional type and with said self-supportingbase end being either a flat plane or defined by the intersection of twoor more flat planes. Alternately, the self-supporting base contour ofsaid blown glass envelope can be a curved surface having either a convexor concave shape with respect to the sides of said glass envelope but ofsuch limited curvature that said envelope physically supports itselfwhen resting on its base end. The sides of the present blown glassenvelope can also be planar or curved in shape with the planar sidedglass envelopes requiring that the mold halves understandably not rotatewhile the glass envelope is being formed.

The basic method of the present invention continuously forms the blownglass envelope from a molten ribbon of glass supported on a movingconveyor by means of:

(a) blowing a portion of the glass from said molten ribbon into thecentral cavity of a multi-part mold, said mold including a pair ofcooperative halves forming the sides of said blown glass envelope byencircling the molten glass while being blown and which mold furtherincludes a separate base part located at the lower end of said cavity toform the self-supporting terminal end of said blown glass envelope, saidbase part of the mold being provided with reciprocal motion in avertical direction,

(b) having the base part of said mold move upwardly and remain in anupward position while the glass envelope is being blown but then moveddownwardly and release the lamp glass envelope before the mold halvesare opened,

(c) opening the mold halves to release the sides of the solidified blownglass envelope, and

(d) severing the blown glass envelope from the moving glass ribbon.

In a preferred form of said method for manufacture of a glass envelopehaving symmetrical curved sides, the mold halves include means to form asteam cushion against which the glass envelope is blown, such as thealready known ventilated paste type mold, and with said mold halvesbeing rotated during formation of the glass envelope. In said preferredmethod, the base part of the mold also includes vent openings to helpventilate the central cavity but generally does not require a pastecoating to form a suitable self-supporting base end for the blown glassenvelope.

In the preferred method of forming glass envelopes having planar sidesaccording to the present invention, both mold halves and the base partremains stationary with respect to each other while the glass envelopeis being blown. The mold parts are also entirely devoid of a pastecoating or ventilation means despite providing a self-supporting baseend on the blown glass envelope which can either be planar or curved. Itis further possible to provide blown glass envelopes according to saidpreferred embodiment from conventional hard glass compositions as wellas soft glass compositions although soft glass would generally beselected for most end product applications involving ordinarytemperature service.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates a fragmentary side elevation view of an exemplaryglass ribbon machine embodying the present invention.

FIG. 2 is a perspective view illustrating a simplified mold designaccording to the present invention.

FIG. 3 is a perspective view illustrating one type glass envelope formedin accordance with the present invention.

FIG. 4 is a perspective view illustrating a different type glassenvelope formed according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, there is partially depicted a conventional hotribbon machine 10 which forms the presently improved glass envelope 12from a molten ribbon of glass 14 that is being carried on a movingconveyor having interconnected orifice plates 16. The molten glass isblown downwardly by blowheads 18 into the central cavity portions ofglass molds 20 constructed in accordance with the present invention. Themold halves 22 are closed while a cylindrically shaped glass envelope isbeing blown while the separate base portion 24 of each mold is movedupwardly and retained in the upward position during this step of themanufacturing process. Downward movement of said base part in the moldsis automatically carried out on said ribbon macine by conventional meansafter the molten glass has solified in the mold cavities as a necessarystep before said mold halves are opened. Rotation of the mold halves 22which is carried out when the glass envelopes are formed in this manneras well as severing the blown glass envelopes from the moving glassribbon after the mold halves have been opened are all carried out in thecustomary manner now being utilized in ribbon machine manufacture.

A simplified mold construction 26 incorporating the essential structuralfeatures required to form the above described blown glass article isdepicted in FIG. 2. Specifically, a pair of mold halves 28 and 30cooperate to form the side portions of the cylindrical blown glassenvelope in a central cavity 32 which terminates in a separate flat basepart 34 of circular contour 35. Vent openings 36 are provided on theupper bare metal surface of said flat base part as an optional means tohelp ventilate the mold cavity. Said base part 34 is also provided withreciprocal motion in a vertical direction by means of being mounted onthe bearing surface 38 and with said upward motion being limited byphysical contact with a rim surface 40 machined at the lower end of thecooperating mold halves. In said mold construction, the cooperating moldhalves are rotated in the customary manner to form the cylindrical glassenvelope and with said mold halves further having vent openings 42 alongwith a paste coating 44 being applied to the inner surface of the centalmold cavity.

In FIG. 3 there is depicted a perspective view of a representative glassenvelope formed as above described and which can be utilized as a liquidcontainer. Said blown glass article 46 includes a cylindrical neckportion 48 terminating at one end in a bulb portion of larger crosssectional dimensions 50 which includes a self-supporting closed end 52of planar configuration 54. As can be observed, the sides and baseportions of the blown glass article are all of relatively uniformlythickness as well as devoid of any physical mold seams.

FIG. 4 is a perspective view of a different blown glass article 60having a straight sided configuration 62 formed by intersection of apair of opposing and parallel flat planes 64 and 66. Said glass articlefurther includes a cylindrical neck portion 70 terminating in a straightsided bulb portion of larger cross sectional dimensions and with thebulb portion of said glass article ending in a self-supporting base 72of convex curvature 74. As can be observed from the drawing, however, avisible mold seam 76 is produced in a said glass article due to nonrotation of the mold halves during the glass forming operation.

While preferred embodiments of the present invention along with improvedmethods for manufacturing said embodiments have been shown anddescribed, various other embodiments along with modifications in thedescribed method of manufacture will become apparent to persons skilledin the art without departing from the true spirit and scope of thepresent invention. For example, it would be apparent from the foregoingdescription that various combinations of planar and curved sides can beemployed for the bulb portion of the blown glass envelope as well as inthe self-supporting base end of said envelope. Accordingly, the scope ofthe present invention is limited only to the following claims.

I claim:
 1. A method of continuously forming a blown glass envelopeterminating in a self-supporting base end from a molten ribbon of glasssupported on a moving conveyor which comprises:(a) blowing a portion ofthe glass from said molten ribbon into the central cavity of a singlemulti-part mold, said mold including a pair of cooperative halvesforming the sides of said blown glass while being blown and which moldfurther includes a separate base part located at the lower end of saidcavity to form the self-supporting base portion of said blown glassenvelope, said base part of the mold being provided with reciprocalmotion in a vertical direction, (b) having the base part of said moldmove upwardly and remain in an upward position while the glass envelopeis being blown to form all structural features in said blown glassenvelope but then move downwardly and release the lamp glass envelopebefore the mold halves are opened, (c) opening the mold halves torelease the sides of the solidified blown glass envelope, and (d)severing the blown glass envelope from the moving glass ribbon.
 2. Amethod as in claim 1 wherein the mold halves include means to form asteam cushion against which the glass envelope is blown while said moldhalves are rotating.
 3. A method as in claim 2 wherein the mold halvesinclude vent openings and a paste coating.
 4. A method as in claim 2wherein the base part of the mold also includes vent openings.
 5. Amethod as in claim 1 using hard glass.
 6. A method as in claim 1 usingsoft glass.
 7. A method as in claim 1 wherein the mold halves do notrotate and are devoid of vent openings.
 8. A method as in claim 7wherein the base part of the mold is also devoid of vent openings.